KR0122095B1 - Inverter and air-conditioner driven by the same - Google Patents

Abstract

The present invention relates to an inverter device, in which the microcomputer 44 compares the terminal voltages Vu to Vw of the windings 35u to 35w by the comparators 38 to 40 with the reference voltage VO. The rotational position of the rotor is detected from the signals Vu 'to Vw', and the rotational flow timing is determined. In the normal case, the microcomputer 44 forms an energization signal corresponding to the current timing in a regular pattern at every rotational flow timing, and sequentially energizes the windings 35u to 35w. When the frost adheres to the outdoor side heat exchanger 58 of the heat pump and the frost needs to be removed during the heating operation of the air conditioner, reverse torque is applied to the rotor of the brushless motor with an energization signal formed by a regular pattern. An energization signal is formed by a loss increasing pattern constituted by adding loss increasing energization signals UpL, VpL, WpL, UnL, VnL, and WnL for generating a. As a result, the loss of the brushless motor 35 increases, and the brushless motor 35 generates heat and is used for defrosting due to heat generated by the brushless motor 35.

Description

Inverter unit and air conditioner controlled by the inverter unit

1 is a circuit diagram showing a first embodiment of the present invention.

2 is a diagram showing an external waveform when the energized signal is formed by a regular inverter together with the measurement time zones of the first and second timer functions.

3 is a waveform diagram of one winding terminal voltage and current.

4 is a second equivalency when the energized signal is formed in a loss increasing pattern.

5 is a waveform diagram of an energized signal, a terminal voltage and a current for one winding when the energized signal is formed in a loss increasing pattern.

6 is a configuration diagram of a heat pump of an air conditioner.

7 is a fourth equivalency of a second embodiment of the present invention.

8 is the fifth equivalent.

9 is a first equivalency of the third embodiment of the present invention.

10 is a configuration diagram of an inverter device controlling a conventional induction motor.

11 shows the relationship between the same voltage and frequency.

12 is a configuration diagram of an inverter device for controlling a conventional brushless motor.

* Explanation of symbols for main parts of the drawings

1: control circuit 2: DC power circuit

3: induction motor 4: switching circuit

5 ~ 10: Transistor 11: Controller

12: brushless motor 13: position detection circuit

14: switching circuit 15-20: transistor

21: AC power supply 22: DC power supply circuit

23: full-wave rectifier circuit 24a: reactor

24b: Condenser 25, 26: DC motor

27 ~ 32: switching transistor 33: three-phase bridge circuit

34u, 34v, 34w: Output terminal 35: 3-phase 4-pole brushless motor

35u, 35v, 35w: winding 36: resistance divider circuit

37: position detection circuit 38 ~ 40: comparator

41 ~ 43: Photo coupler 44: Microcomputer

Ua, Va, Wa: Recognition waveform signal X1 to X6: First phase classification

Y1 ~ Y6: 2nd phase classification Up, Un, Vp, Vm, Wp, Wn: Communication signal

Sd: Duty signal P1: PWM signal

45 pulse width modulation circuit 46 gate circuit

47 ~ 52: Gate part Vu ', Vv', Vw ': fundamental wave signal

UnL, WpL, VnL, WnL, VpL: Loss increasing energization signal

53 compressor 54 compression unit

55: 4-way valve 56: Indoor side heat exchanger

57: decompression device 58: outdoor side heat exchanger

59, 60: Fan 61 ~ 64, 67: Temperature sensor

The present invention relates to an inverter device having a switching circuit for sequentially energizing a plurality of phase windings of a brushless motor for driving a compressor of a heat pump to current timing corresponding to a predetermined rotational position of the motor, and controlled by the inverter device. It relates to an air conditioner.

For example, in a heat-pumped air conditioner, the outdoor side heat exchanger functions as a condenser when cooling indoors and as an evaporator when heating indoors, but the outdoor temperature of the outdoor unit during winter heating (external) When the temperature is lowered, frost is generated in the outdoor heat exchanger and the heating capacity is reduced.

Therefore, in the heat pump type air conditioner, the defrosting operation for removing the frost attached to the outdoor side heat exchanger during the heating operation is performed. The defrosting operation method uses a four-way valve to replace the heat pump with a cooling cycle to operate it (the external side heat exchanger is replaced with a condenser) and the four-way valve is maintained against the heating cycle. And a bypass path for direct delivery of the refrigerant to the outdoor side heat exchanger. In all of these defrosting operations, the high temperature discharge refrigerant of the compressor is sent directly to the outdoor side heat exchanger to raise the temperature of the outdoor side heat exchanger to melt the frost attached thereto.

On the other hand, the necessity of defrosting operation, that is, the detection of frost attached to the outdoor side heat exchanger is generally detected by the temperature of the outdoor side heat exchanger falling below a predetermined temperature, but not limited to this, but the magnitude of the temperature change of the indoor side heat exchanger. Detecting the magnitude of the difference in temperature from the outdoor side heat exchanger, or by combining these temperature changes with time, ie by the magnitude of these temperature changes (temperature change rate) per unit time, etc. These are the known ones.

However, during the defrosting operation, the heating capacity for the room deteriorates or the heating capacity is completely lost. Therefore, it is desirable to finish the defrosting operation in a short time as much as possible to reduce the decrease in room temperature. In order to shorten the defrosting operation time, the heat generated by the drive motor, especially the driving motor, of the compressor which has been constructed in the outdoor machine together with the outdoor side heat exchanger has been conventionally used for melting of the frost. It is required that the amount of heat generated by the rotor is large, that is, the motor efficiency is low and the loss is large.

Recently, in air conditioners, induction motors are controlled by inverter devices in order to change the capacity of compressors and save power consumption, or brushless motors, which are a type of DC motors, are controlled by inverter devices.

10 shows an outline of the electrical configuration when the induction motor is controlled by the inverter device. The control circuit 1 is a voltage applied to the windings of each phase of the induction motor 3 in the DC power supply circuit 2; In order to control the frequency, the transistors 5 to 10 of the switching circuit 4 are controlled on and off. In general, high-efficiency operation is realized by controlling the voltage and frequency applied to the induction motor 3 so as to be in the relationship shown in FIG.

12 shows an outline of the electrical configuration when the brushless motor is controlled by the inverter device. The control device 11 is provided from the position detection circuit 13 for detecting the rotor rotation position of the brushless motor 12. The high-efficiency operation is performed by turning on and off the transistors 15 to 20 of the switching circuit 14 based on the detected signal. In addition, speed information is obtained from the position detection signal, the speed command signal is compared, and the speed control is performed by the pulse width modulation method.

When the induction motor or brushless motor is controlled by the inverter device, the induction motor does not control the frequency and voltage in the defrost operation in the relationship shown in FIG. The heat loss can be increased to increase the amount of heat generated. However, in the case of brushless motors, the loss cannot be increased by manipulating the relationship between frequency and voltage, so the operation is efficient even during defrosting operation. Therefore, the heat of the motor (compressor) can be used for defrosting. And it takes time to defrost, and there is an irrationality that the room temperature is lowered and the comfort is lowered. In addition, when the air conditioner requires heat generation of the compressor, there is a deterioration of the compressor temperature during defrost preparation operation or normal operation, in addition to defrost operation. Defrost preparation operation is to heat up the compressor before starting defrost operation to shorten the defrost operation time, and use the heat stored in the compressor to remove the defrost. Runs just before entering This defrost preparation operation stops the indoor fan sending indoor air to the indoor heat exchanger while maintaining the heat pump according to the heating cycle, compresses the pressure reducing device, or increases the motor rotation speed of the compressor higher than the command value based on room temperature. Is executed. When the temperature of the compressor reaches a predetermined value as a result of the defrost preparation operation or when the defrost preparation operation is executed for a predetermined time, at least one of the conditions is satisfied, the defrost operation is terminated and replaced by the defrost operation. It is configured to be.

Since the defrost preparation operation stops the indoor fan or compresses the decompression device as described above, it is necessary to complete this defrost preparation operation in the shortest possible time in order to minimize the decrease in the room temperature.

In addition, during normal operation, the temperature of the compressor is maintained at a high temperature of about 80 ° C. However, if the motor is repeatedly turned on and off for a short time, the compressor temperature does not rise and the operation of the compressor is low. Is executed. At this time, when the difference between the temperature of the heat exchanger (inside heat exchanger during heating operation and the outdoor side heat exchanger during cooling operation) and the compressor temperature decreases, the refrigerant melts in the lubricating oil in the compressor. In this case, it is also necessary to raise the temperature of the compressor in a short time because the viscosity of the resin may be lowered, thereby reducing the lubricating performance and damaging the compressor.

As described above, in the heat pump air conditioner, it is often necessary to raise the temperature of the compressor such as deterioration of the compressor during operation other than during defrosting operation. However, even in such a case, when a brushless motor controlled by an inverter device is adopted as the motor for driving the compressor, it is difficult to perform an operation that increases the loss of the brushless motor and heats the brushless motor. There is a problem in that it cannot be used for heat generation and the comfort and reliability are lowered compared to the case of using an induction motor.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air conditioner controlled by an inverter device and an inverter device capable of increasing loss by lowering motor efficiency at a predetermined time in adopting a brushless motor as a driving motor of a compressor of a heat pump. It is.

An inverter device according to the present invention comprises: a switching circuit comprising a plurality of switching elements which in turn electrically conduct a plurality of coils in a brushless motor for driving a compressor of a heat pump; A pulse width modulation circuit for generating a pulse width modulation signal; Position detecting means for detecting a rotor rotation position of the brushless motor; A driving circuit for determining the current timing based on the detection signal of the position detecting means, the energizing signal forming means for forming an energizing signal corresponding to the current timing, and synthesizing the energizing signal and the pulse width modulation signal to drive the switching element; The energization signal forming means has two normal patterns based on the current timing as the two formation patterns of the energization signal, and a loss increasing pattern to which the energization signal for increasing the deterioration of driving efficiency is added to the regular pattern. And converting the loss pattern into a loss increasing pattern at a predetermined time.

According to the present invention configured as described above, the brushless motor can be operated with high efficiency since the energization signal is formed in a normal pattern in a normal case. If the switching pattern of the energizing signal is changed to the loss increasing pattern at a predetermined time, the heat efficiency of the brushless motor increases because the motor efficiency decreases.

Inverter device according to the present invention comprises a switching circuit consisting of a plurality of switching elements in order to electrically pass through the plurality of coils of the brushless motor for compressor drive of the heat pump in order; A pulse width modulation circuit for generating a pulse width modulation signal; Position detecting means for detecting a rotational position of the rotor of the brushless motor based on a comparison result between the terminal voltage of the winding and a reference voltage; A driving circuit for determining the current timing based on the detection signal of the position detecting means, the energizing signal forming means for forming an energizing signal corresponding to the current timing, and synthesizing the energizing signal and the pulse width modulation signal to drive the switching element; The energization signal forming means includes a normal pattern based on the current timing and a loss increase pattern added with a loss signal for increasing driving efficiency. It is characterized in that the switching to a loss increasing pattern from a normal pattern at a predetermined time.

According to the present invention configured as described above, the position detection sensor may not be provided because the rotation position of the rotor is detected as a result of the comparison between the terminal voltage of the winding of the brushless motor and the reference voltage.

In this case, the reference voltage may be set to one-half the DC power supply voltage of the switching circuit, and the position detecting means may be configured to output a detection signal when the terminal voltage of the winding crosses the reference voltage.

In the inverter device of the present invention, the energization signal formed by the loss increasing pattern is configured by adding an energization signal for increasing the loss to generate reverse rotation torque to the rotor of the brushless motor to the energization signal formed by the regular pattern. can do.

In this case, since the heat generation amount of the brushless motor is changed, the loss can be controlled somewhat by changing the time width of the energization signal for increasing the loss.

In the inverter device of the present invention, in order to easily determine the rotational flow timing by the program software, the position detecting means is positioned when the reference voltage set to 1/2 of the terminal voltage of the winding and the DC power supply voltage of the switching circuit cross each other. The detection signal is output and the energization signal forming means includes a first timer that counts the time from the point where the terminal voltage and the reference voltage of the winding cross to the next cross point, and the terminal voltage of the winding based on the count time of the first timer. Calculating means for calculating the time from the point of time when the reference voltage crosses the reference voltage to the rotational flow timing, and a second timer for counting the time calculated by the calculating means, and counting the time when the second timer has finished the time count. The current timing can be configured. In this case, the energizing signal formed by the loss increasing pattern is formed by adding the loss increasing energizing signal for generating reverse rotation torque to the brushless motor rotor to the energizing signal formed by the regular pattern. The means has a third timer that counts the time corresponding to the time width of the loss increasing energized signal at the time when the terminal voltage and the reference voltage of the winding cross, and immediately after the time when the terminal voltage and the reference voltage of the winding cross. The third timer may be configured to form a loss increasing energization signal until the third timer ends the time count.

The air conditioner of the present invention comprises a compressor driven by a brushless motor, an outdoor side heat exchanger, a decompression device, and a heat pump configured by connecting an indoor side heat exchanger by a refrigerant pipe, and describes the brushless motor in detail. It is characterized by controlling by the inverter device as described.

According to such an air conditioner, for example, when a brushless motor is driven by an energization signal formed by an increase pattern of defrosting operation, the brushless motor generates heat and can be used to remove the heat in a short time. The removal operation can be terminated.

EXAMPLE

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6 by applying to a case where a brushless motor for driving a compressor of a heat pump of an air conditioner is controlled by a pulse width modulation (hereinafter, simply PWM) method. . First, in this embodiment, the rotor rotation position signal of the brushless motor is obtained by detecting the induced voltage of the winding and electrically processing it.

In the inverter device shown in FIG. 1, the current power supply circuit 22 connected to the AC power supply 21 includes a full-wave rectification circuit 23, a reactor 24a, and a smoothing capacitor 24b. 22, the three-phase bridge circuit 33 composed of switching elements, for example, switching transistors 27 to 32, is connected between the DC bus lines 25 and 26, and its output terminals 34u, 34v, 34w. For example, each winding 35u, 35v, 35w of the brushless motor 35 of the three-phase four-pole is connected.

In the three-phase bridge circuit 33, the three transistors 27, 29, 31 connected between the DC bus 25, which is the + side of the DC power supply circuit 22, and the output terminals 34u, 34v, 34w, The three transistors 28, 30, 32 corresponding to the positive side switching element and connected between the negative side DC bus 26 and the output terminals 34u, 34v, 34w correspond to the negative side switching elements. When each of the transistors 27 to 32 is controlled on and off in a predetermined order, the brushless motor 35 sequentially rotates the windings 35u to 35w of the respective phases with a phase difference of 120 degrees (electric angle). It is rotated by energizing repeatedly. In this case, one transistor is controlled by an on / off cycle of 120 degrees on and 240 degrees off, and in the on cycle, the duty is controlled by the PWM signal P1 shown in FIG. The terminal voltages Vu, Vv, and Vw of the respective windings 35u to 35W of 35 become the waveforms shown in the second (b) to (d).

3 (a) and 3 (b) show the waveforms of the terminal voltage Vu and the current Iu of one winding 35u without the PWM control. In the waveform of the double terminal voltage, the inclined portion over the interval of about 60 degrees (period Ta) is the induction voltage of the winding and the long side pulse is connected to the diode D connected in parallel with each transistor of the three-phase bridge circuit 33. Pulse voltage or VO is a reference voltage formed by the resistance voltage dividing circuit 36 connected between the DC motors 25 and 26. It can be understood from FIG. 3 that the rotational flow timing occurs about 30 degrees later at the time when the induced voltage and the reference voltage VO cross (hereinafter referred to as zero cross time).

The terminal voltages Vu, Vv, and Vw are compared with the reference voltage VO by the comparators 38 to 40 provided in the position detecting circuit 37 as position detecting means. Is converted into a fundamental wave signal Vu ', Vv', Vw 'for 180-degree interval recognition of the terminal voltages Vu to Vw as shown in FIG. Again, these fundamental wave signals Vu ', Vv', Vw 'are supplied from the position signal circuit 37 to the microcomputer 44 as the energization signal forming means through the photocouplers 41-43, and the microcomputer 44 ) Is converted into recognition waveform signals Ua, Va, and Wa having a continuous square wave of 180 degrees in time width only with the constant pulse component as shown in FIGS. 2 (k) to (m), and having a phase difference of 120 degrees. . The starting point (rising point) and the ending point (falling point) of the recognition waveform signals Ua, Va, and Wa coincide with each other when the induced voltage crosses the reference voltage VO.

In the microcomputer 44, as shown in FIG. 2 (d), the first and second timer functions (first and second timers) held by the microcomputer 44 are used by the first timer function. From the recognition waveform signals Ua, Va, and Wa, six first phase classification patterns X1 to X6 each having a time width Tb of 60 degrees are formed, and the first phase separation pattern is formed by the second timer function. Six second phase discrimination patterns Y1 to Y6 each having a time width of 30 degrees starting from the end point of (X1 to X6) are formed. The microcomputer 44 finally synthesizes the energization signals Up, Un, Yp, Vn, Wp and Wn shown in Figs. 2 (o) to (t) from the second phase separation signal as described above.

Here, since the starting point of the energization signal Up, Un, Yp, Vn, Wp, Wn coincides with the end point of the second phase separation pattern Y1 to Y6, at the point where the induced voltage crosses the reference voltage VO, It is a time point occurring after 30 degrees, and therefore, the phase patterns of the energization signals Up, Un, Vp, Vn, Wp, Wn are required for the rotational flow timing required for the transistors 27 to 32 of the three-phase bridge circuit 33. Will match the pattern.

On the other hand, the microcomputer 44 has a time of 6 patterns (brushless motor half rotation) or 12 patterns (brushless motor one rotation) before the current phase division pattern in the first phase separation patterns X1 to X6. The rotation speed per unit time of the brushless motor is determined from the summation, and this is compared with the speed command value to determine the speed deviation, and the duty signal Sd corresponding to the speed deviation is converted into the pulse width modulation circuit 45. To give. The pulse width modulation circuit 45 then outputs a PWM signal P1 having a duty indicated by the duty signal Sd.

The PWM signal P1 of which the duty is controlled as described above is applied to the energization signals Up and Vp by the gate parts 47, 49, and 51 among the gate parts 47 to 52 of the gate circuit 46 constituting the driving circuit. Wp) and a combination, for example, a logical product, are supplied as a phase control signal to the base of each transistor 27, 29, 31 of the three-phase bridge circuit 33. As a result, the brushless motor 35 continues to drive while the transistors 27 to 32 are controlled on and off by the energization signals Up to Wn of the pattern shown in Figs. 2 (o) to (t). At the same time, the speed control is performed by the duty control by the PWM signal P1 shown in FIG. 2 (a).

In addition, the terminal voltages Vu, Vv and Vw and the fundamental wave signals Vu ', Vv' and Vw 'are actually waveforms opposite to the PWM signal, but the second (b) to (d) are also (h) to ( It is omitted in the diagram j). The pattern of the energization signals Up to Wn formed as described above corresponds to a regular pattern for operating the brushless motor 35 with high efficiency. In normal operation, the brush motor 35 is controlled with this regular pattern. do.

Next, the energization signal of the loss increase pattern with low motor efficiency used for defrost operation | operation is demonstrated. In addition, the control operation in defrost operation of the heat pump air conditioner will be described later.

Referring to FIG. 4, this loss increasing pattern is shown in the same drawing (o) to (t). As shown in FIGS. It is the same as the normal energized signal pattern except that UnL, WpL, UpL, WnL, and VpL) are formed.

In other words, upon the execution of the loss increase pattern, the third timer function (third timer) held in the microcomputer 44 performs the timer operation. The third timer function measures the loss increasing energization signal formation period Z1 to Z6 of the time width starting from the end point of each of the first phase division patterns X1 to X6. Then, the microcomputer 44 increases the loss increasing energization signals UnL, WpL, VnL, UpL, WnL, immediately after the start of the loss increasing energization signal forming periods Z1 to Z6 to the end point of the period Z1 to Z6. VpL).

This loss increasing current signal (UnL, WpL, VnL, UpL, WnL, VpL) causes a current reverse to the normal state to the windings (35u, 35v, 35w) in each of the first phase division patterns (X1 to X6). Flows and generates reverse torque. As a result, the efficiency of the brushless motor is lowered and the loss is increased, thereby increasing the current flowing through each of the windings 35u, 35v, and 35w, and increasing the amount of heat generated.

Here, the time width Tc of the loss increasing energization signal formation period Z1 to Z6 is changed short and long as shown in (a) to (d) and (e) to (h) shown only for one winding 35u. It is comprised so that the loss of the brushless motor 35 and the heat generation amount can be increased and decreased by this. The time width Tc of the loss increasing energization signal formation periods Z1 to Z6 is configured to maximize the time corresponding to half of the time width Tb of the first phase separation patterns Z1 to Z6.

6, the relationship between the control operation and the control of the brushless motor 35 in the defrost operation of the heat pump type air conditioner will be described.

First, the compressor 53 is configured by storing the compression unit 54 and the brushless motor 35 in the same steel hermetic container 53a, and the rotor shaft of the brushless motor 35 is connected to the compression unit 54. It is. The compressor 53, the four-way valve 55, the indoor side heat exchanger 56, the pressure reducing device 57, and the outdoor side heat exchanger 58 are connected to each other so as to be a closed loop by a pipe which is a refrigerant pipe.

At the time of heating, the four-way valve 55 is in a solid line, and the high temperature refrigerant compressed by the compression unit 54 of the compressor 53 is supplied to the indoor side heat exchanger 56 from the four-way valve 55 to retain the shaft. Then, the pressure is reduced in the depressurization apparatus, becomes a low temperature, flows to the outdoor side heat exchanger 58, and evaporates here, and returns to the compressor 53.

At the time of cooling, the four-way valve 55 is switched to a state indicated by broken lines. For this reason, the high temperature refrigerant compressed by the compression section 54 of the compressor 53 is supplied to the outdoor side heat exchanger 58 from the four-way valve 55 to be refrigerated, and then depressurized by the decompression device 57 and becomes low temperature. It flows to the heat exchanger (56) and evaporates here and returns to the compressor (53). The heat exchangers 56 and 58 on the indoor side and the outdoor side are blown by the fans 59 and 60, respectively, and the air is blown by the blowers to the heat exchangers 56 and 58. In addition, the heat exchange with the outdoor air is efficiently performed.

At the time of operation, the room temperature is detected by the temperature sensor 61 provided on the air suction side of the indoor side heat exchanger 56, and the detection signal is input to the microcomputer 44. Then, the speed command value of the brushless motor 35 is set by the microcomputer 44 based on the difference between the detection temperature ta set temperature of the temperature sensor 61 and the PWM signal P1 as described above. Speed control of the brushless motor 35 is performed by the duty control.

In addition, the outdoor side heat exchanger 58 is provided with a temperature sensor 62 for detecting a state of frost caused by the temperature ta, and the detection signal of the temperature sensor 62 is input to the microcomputer 44. In addition, a temperature sensor 63 for detecting the compressor temperature tc is installed in the vessel 53a of the compressor 53, and a temperature sensor 64 for detecting the temperature td is provided in the indoor side heat exchanger 56, and each detection signal is provided. Is input to the microcomputer 44.

Here, the control operation of the microcomputer 44 will be described.

When the microcomputer 44 determines that the frosted state of the outdoor side heat exchanger 58 has become necessary to remove the frost at the detected temperature tb of the temperature sensor 62, the frost removal preparation operation is started. This defrost preparation operation maintains the heat pump in the heating cycle, and slows down or stops the indoor fan 59 or compresses the decompression device 57 and sets the rotational speed of the brushless motor 35 based on the room temperature ta. By raising more, the compressor 53 heats up.

In addition, the determination of the start of the defrosting preparation operation is not limited to the determination of the temperature of the outdoor side heat exchanger 58, but the magnitude of the temperature change of the indoor side heat exchanger 56 is determined by the temperature of the indoor side heat exchanger 56 and the room temperature. The magnitude of the change of the difference, the magnitude of the difference between the outdoor side heat exchanger 58 and the external temperature, the magnitude of these temperature changes per unit time, etc. are known and available.

When the defrosting preparation operation is started, the microcomputer 44 switches the inverter device 33 from the normal operation by the normal energization signal pattern to the operation by the loss increase pattern with lower efficiency of the motor than the normal pattern. As a result, during the defrost preparation operation, not only the compressor 54 but also the brushless motor 35 generate heat, the amount of heat generated by the compressor 53 is larger than usual and the temperature of the compressor 53 rises in a short time. Defrost ready operation when the temperature tc of the compressor 53 detected by the temperature sensor 63 becomes equal to or greater than the predetermined value or when at least one condition is satisfied when the defrost preparation preparation time has elapsed for a predetermined time. Exit and switch to defrost operation.

Here, the defrosting operation after completion of the defrosting preparation operation is switched to a cooling cycle by the four-way valve 55, or the discharged refrigerant of the compressor 53 is directly transferred to the outdoor heat exchanger 58 while the four-way valve 55 is kept in the heating cycle state. This is performed by opening or closing the normally open / closed valve 66 installed in the bypass passage 65 to be sent to the inlet. Even when the defrosting preparation operation is switched to the defrosting operation after the end of the defrosting preparation operation, the microcomputer 44 instructs the inverter device 33 of the low efficiency of the motor and continues the operation by the loss increasing pattern. Therefore, a large amount of heat is generated from the brushless motor 35 even during the defrosting operation and is used as the defrosting heat. Defrosting time can be significantly shortened. After that, when the temperature rise of the outdoor side heat exchanger 58 is detected by the temperature sensor 62, the microcomputer 44 determines that the defrosting is completed, and in the case of the defrosting operation switched to the cooling cycle, the four-way valve 55 is opened. In the defrosting operation which returns to the heating cycle position and the bypass passage 65 is opened, the on-off valve 66 is closed to return to the heating operation.

In response to the return of the heating operation, the microcomputer 44 switches from the operation by the loss increasing pattern to the regular pattern operation with good efficiency.

In addition, since the temperature of the coolant decreases after the end of the defrosting operation, the timer is operated after the end of the defrosting is completed, instead of switching to a normal pattern immediately after the end of the defrosting to improve the lubricity of the lubricant in the compressor 53. You may switch to regular pattern operation later.

Next, the temperature decrease of the compressor 53 in operation is demonstrated. During normal operation, the temperature of the compressor 53 is maintained at a high temperature of about 80 ° C. However, if a condition such as repeating the on / off of the brushless motor 35 for a short time occurs, the temperature of the compressor 53 does not rise. Operation is performed in a state where the temperature of the compressor 53 is low. At this time, if the difference between the temperature of the heat exchanger (the temperature of the indoor side heat exchanger 56 in the heating operation and the temperature of the outdoor side heat exchanger 58 in the heating operation) on the side of the condenser becomes smaller than the temperature of the compressor 53, The refrigerant melts in the lubricating oil in the container 53a, and the viscosity of the lubricating oil is lowered, which may lower the lubricating performance and cause damage to the compressor 53.

To prevent this, it is effective to detect the temperature of the compressor 53 and the temperature of the heat exchanger on the side of the condenser during operation, and heat the compressor 53 itself when the temperature difference drops below a predetermined value.

Therefore, when the difference between the compressor temperature tc detected by the temperature sensor 63 during the heating operation and the detected temperature td of the temperature sensor 64 installed in the indoor side heat exchanger 56 becomes less than a predetermined value, the microcomputer 44 brushes the brush. The Less Motor 35 is switched from the regular pattern to the operation by the loss increasing pattern. On the other hand, when the difference between the compressor temperature tc detected by the temperature sensor 63 and the detection temperature tb of the temperature sensor 62 installed in the outdoor side heat exchanger 58 becomes less than a predetermined value during the cooling operation, the microcomputer 44 brushes. The Less Motor 35 is switched from the regular pattern to the operation by the loss increasing pattern. As a result, since the loss of the brushless motor 35 increases and the temperature of the compressor 53 increases, the viscosity of the lubricating oil is eliminated, and the reliability of the compressor 53 can be improved.

When the brushless motor 35 is operated in a loss increasing pattern while the temperature of the compressor 53 during the defrosting preparation operation, the defrosting operation, and the normal operation is reduced as described above, the microcomputer 44 generates a loss increasing energization signal. The time width Tc of (UnL, WpL, VnL, UpL, WnL, VpL) is the temperature tb of the outdoor side heat exchanger 58 detected by the temperature sensor 62, and the compressor temperature tc detected by the temperature sensor 63. And the time width according to the magnitude of the difference between the temperature td of the indoor side heat exchanger 56 detected by the temperature sensor 64 or the temperature tb of the outdoor side heat exchanger 58 detected by the temperature sensor 62. The amount of heat generated by the brushless motor 35 is set to an amount necessary in each case.

The microcomputer 44 also receives a detection signal te from the temperature sensor 67 for detecting the ambient temperature of the three-phase bridge circuit 33. When the detection temperature te of the temperature sensor 67 exceeds the predetermined temperature while the microcomputer 44 performs the operation by the loss increasing pattern during the defrosting operation, the loss increasing energization signal formation period (Z1 to Z6) is performed. By shortening the time width Tc, the amount of heat generated by the brushless motor 35 is suppressed to protect the switching transistors 27 to 32 and the like from abnormal high temperatures.

As described above, according to the present embodiment, even the brushless motor 35 controlled by the inverter device 33 includes a brush such as a temperature decrease of the compressor 53 during defrost preparation operation, defrost operation, and normal operation. When it is necessary to increase the calorific value of the Lesser motor 35, the efficiency can be lowered to increase the calorific value, and as a result, the defrosting time of the indoor side heat exchanger 56 can be shortened and the compressor 53 can be reduced. The reliability can be improved.

In addition, when controlling the brushless motor 35 by a loss increasing pattern, the loss increasing energization signal (UnL, WpL, VuL, UpL, WnL, VpL) is determined immediately after the rotational flow timing is determined. Because the terminal voltages (Vu, Vv, Vw) cross the reference voltage (VO) after a very short time elapses, they are formed by the loss-increasing energization signals (UnL, WpL, VnL, UpL, WnL, VpL). The terminal voltages Vu, Vv, and Vw appear at the + side or the-side potential of the DC power supply circuit 22, and it is not possible to detect when the induced voltage crosses the reference voltage VO. There is no fear of causing it.

In this embodiment, the time between the zero cross point and the zero cross point is measured by the first timer function, and the time from the zero cross point to the current timing is calculated based on the measured time. Since the time is counted by the second timer function, and the second timer function ends the time count, the rotation flow timing is used. Therefore, the time from the zero cross point to the rotation flow timing depends on the rotor speed. Even if it is different, the rotational flow timing can be easily determined by a computer program.

In addition, since the time width of the loss increasing energization signal (UnL, WpL, UnL, UpL, WnL, VpL) is similarly measured by the third timer function, the time width can be easily determined by the computer program as well.

In this embodiment, the positional information of the rotor is obtained by comparing the winding terminal voltages Vu, Vv and Vw with the reference voltage VO. Therefore, the position detection sensor does not need to be provided. In particular, since the reference voltage VO is set to 1/2 of the voltage of the DC power supply circuit 22, two potentials different from high and low need not be set as reference voltages. The reason is that when the reference voltage is set to a potential different from one-half of the voltage of the DC power supply circuit 22, the cross point between the terminal voltages (Vu, Vv, Vw) and the reference voltage is determined by the rotational flow timing. Since it is not fixed uniformly, it becomes difficult to determine the rotational flow timing. In order to avoid this, it is necessary to set the reference voltage to two potentials different from high and low, and make sure that the cross point between the terminal voltages (Vu, Vv, Vw) and the reference voltage is set constant in relation to the rotational flow timing. .

In the above embodiment, the rotational flow timing was determined based on the comparison result between the terminal voltages Vu, Vv, and Vw and the reference voltage VO. However, this method detects the position of the rotor by magnetism of the permanent magnet of the rotor. A magnetic detection element such as a hall element to be performed may be provided, and the rotational flow timing may be determined based on the detection signal of the magnetic detection element.

FIG. 11 shows the loss increasing pattern of the second embodiment of the present invention. In this embodiment, the third timer function is not provided and the measurement start of the second phase separation patterns Y1 to Y6 by the second timer function is started. In the case of synchronizing loss increasing energization signals (UnL, VnL, WnL) forming the loss increasing energization signals (UnL, WpL, UpL, WnL, and VpL) from immediately after the end of measurement, the energization signals (Vn, Wn, Un) In this case, the energizing signals Up, Vp, and Wp are not formed when the loss increasing energizing signals WpL, UpL, and VpL are formed.

Also, in the present embodiment, the time width of the second phase separation patterns Y1 to Y6 is long and short as shown in Figs. 8A and 8B shown for one winding 35u. Thereby, the amount of heat generated by the brushless motor 35 is adjusted according to the temperature of the outdoor side heat exchanger.

In such a configuration, in the second phase separation patterns Y1 to Y6, any one of the transistors 27, 29 and 31 on the + side is applied to the loss increasing energization signals UpL, WpL, and VpL. When driving, the other positive side transistor is not driven, and when driving any one of the transistors 28, 30, 32 on the negative side by the loss increasing energization signal UnL, WnL, VnL, the other side The transistor of is not driven. As a result, it is possible to make the current flow as much as possible for the winding that generates the positive torque, and to make the current flow as much as possible for the winding that generates the reverse torque. Therefore, the brushless motor efficiency is lowered and the loss is increased. The current flowing through (35u, 35v, 35w) increases and the amount of heat generated increases.

9 shows a third embodiment of the present invention, in which parts identical to those of the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. In other words, a current transformer 69 serving as a current detecting means is provided in one of the power supply lines 68 connecting the AC power supply 21 and the DC power supply circuit 22, and the signal of the current transformer 69 is a detection circuit 70. Is input to the microcomputer 44. The microcomputer 44 detects the current supplied to one of the power supply lines 68 and further the three-phase bridge circuit 33 by the detection signal from the current transformer 69, whereby the energization signal is lost in the regular pattern. Find the increase of the current when changing to the increase pattern. Then, the time increase of the loss increasing energization signal (UnL, WpL, VnL, UpL, WnL, VpL) is corrected so that the current increase becomes the loss equivalent described on the basis of the detection temperature of the temperature sensors 62 to 67, and brushless mower. The magnitude of the calorific value of the rotor 35 is corrected. The current detection supplied to the three-phase bridge circuit 33 may detect the current flowing through the DC bus 25 or 26.

Claims (13)

A switching circuit composed of a plurality of switching elements which in turn electrically pass through a plurality of coils in a brushless motor for driving a compressor of a heat pump; A pulse width modulation circuit for generating a pulse width modulation signal; Position detecting means for detecting a rotor rotation position of the brushless motor; A driving circuit for determining the current timing based on the detection signal of the position detecting means, the energizing signal forming means for forming an energizing signal corresponding to the current timing, and synthesizing the energizing signal and the pulse width modulation signal to drive the switching element; The energization signal forming means includes a normal pattern based on the current timing and a loss increase pattern added with a loss signal for increasing driving efficiency. Inverter device, characterized in that to switch from the regular pattern to the loss increasing pattern at a predetermined time. The inverter device according to claim 1, wherein the position detecting means detects a rotor rotation position of the brushless motor based on a result of comparing the terminal voltage of the winding with a reference voltage. 3. The reference voltage according to claim 2, wherein the reference voltage is set to one half of the DC power supply voltage of the switching circuit, and the position detecting means outputs the position detecting signal when the terminal voltage of the coil and the reference voltage cross each other. Inverter device. The energization signal of claim 1 or 2, wherein the energization signal formed by the loss increasing pattern is configured by adding a loss increasing energization signal for generating reverse rotation torque to the rotor of the brushless motor to the energization signal formed by the regular pattern. Inverter device characterized in that. 5. The switching element according to claim 4, wherein the switching element comprises a plurality of positive side switching elements connected between the + side of the DC power circuit and the terminals of the coil and a plurality of negative side switching elements connected between the negative side of the DC power circuit and the terminals of the coil. When the energization signal forming means forms a loss increasing energization signal for driving one positive side switching element, it does not form an energization signal for driving the other positive side switching element and increases the loss driving one negative side switching element. And an energization signal for driving the other side switching element when the energization signal for power is formed. The energization signal of claim 2 or 3, wherein the energization signal formed by the loss increasing pattern is formed by adding a lossy energization signal for generating reverse rotation torque to the rotor of the brushless motor to the energization signal formed by the regular pattern. And the energizing signal forming means forms the loss increasing energizing signal after the rotational flow timing is determined by comparing the terminal voltage and the reference voltage of the coil. 5. The inverter device according to claim 4, wherein the energization signal forming means controls the loss largely by changing the time width of the loss increasing energization signal. The current detecting means for detecting a current supplied to the switching circuit is provided, and the energizing signal forming means corrects the time width of the loss increasing energizing signal based on the detected current of the current detecting means. Inverter device. 4. The energizing signal forming means according to claim 3, further comprising: a first timer for counting a time from a point where the terminal voltage of the coil crosses the reference voltage to the next point of crossing; Calculation means for calculating the time from the time when the terminal voltage of the coil and the reference voltage cross to the rotational flow timing based on the count time of the first timer, and a second timer for counting the time calculated by the calculation means. And wherein the second timer sets the time of ending the time counter as the rotational flow timing. 10. The energization signal of claim 9, wherein the energization signal formed by the loss increasing pattern is formed by adding a loss increasing energization signal for generating reverse rotation torque to the rotor of the brushless motor to the energization signal formed by the regular pattern. The forming means includes a third timer for counting a time corresponding to the time width of the loss-in-energizing signal when the terminal voltage and the reference voltage of the coil cross each other, and the point of time when the terminal voltage and the reference voltage of the coil cross each other. And an energization signal for increasing loss between the third timer and the end of the time count. The air conditioner according to claim 1 or 3, further comprising a heat pump configured by connecting a compressor driven by a brushless motor, an outdoor side heat exchanger, a pressure reducing device, and an indoor side heat exchanger with a refrigerant pipe. An air conditioner characterized in that the motor is controlled by an inverter device. 12. The lossless pattern of the brushless motor according to claim 11, wherein at least one of the defrosting operation for removing the frost caught in the outdoor heat exchanger and the defrosting preparation operation performed before the defrosting operation is performed. Air conditioner, characterized in that controlled by. 12. The apparatus of claim 11, further comprising: a temperature sensor detecting a temperature of the compressor; A temperature sensor for detecting a temperature of a heat exchanger of a side functioning as a condenser in a temperature sensor of an indoor side heat exchanger and an outdoor side heat exchanger, and means for calculating a temperature difference detected by the two temperature sensors; An air conditioner characterized in that the brushless motor is controlled by a loss increasing pattern when the difference in detection temperature is less than or equal to a predetermined value.